Strap for 1815 Rattrapante Perpetual Calendar Platinum

The A. Lange & Söhne 1815 421.025 features a lug width (ansa width) of 20mm. This measurement is specific to this model and corresponds to the distance between the inner walls of both lugs. A compatible strap must fit without forcing and without visible gaps between the lug and the strap itself.

The best strap depends on intended usage. Dark brown alligator is the most authoritative choice for formal elegance, as its natural grain contrasts gently with the platinum case. Burgundy shell cordovan offers chromatic depth and exceptional ageing patina. Natural cognac vegetable-tanned calfskin is ideal for those preferring initial comfort and a softer palette. Black rubber with platinum deployante ensures sporting practicality without compromising sobriety.

To change the strap, obtain an appropriate spring bar tool. Angle the tool under the lug to compress the internal spring mechanism, release one side at a time, and withdraw the strap. When reinstalling, ensure the bar is fully engaged and the spring is released. Recommendation: entrust this operation to a watchmaker if inexperienced, to avoid scratching the platinum case.

Yes. 20mm aftermarket straps are rare but available from specialist strap artisans such as milanostraps.it, offering alligator, cordovan, calfskin and rubber solutions. Before purchasing, verify the lug width precisely with a digital calliper, as a 0.5mm error can compromise fitment. Casati Milano additionally offers bespoke service with personal leather selection in the Milanese atelier.

Durability depends on material and usage. A quality alligator or shell cordovan strap, with moderate daily use, lasts 3-5 years before requiring maintenance or replacement. Exposure to perspiration, moisture and stress shortens service life. Vegetable-tanned calfskin has slightly lower durability (2-3 years) but ages more beautifully aesthetically. Rubber straps resist 4-6 years if not exposed to extreme temperatures. Casati Milano guarantees artisanal straps for 18 months against production defects.